As far as Prague goes, the Taxi's being a ripoff is good advice. I lived there in the past, and this is the truth.

One night, going from near Wilsonova (close to Hlavni Nadrazi) to Zizkov (near Chmlenice tram stop) a taxi that should have cost $5 was going to cost $50. Of course, we didn't pay that fare, gave him the normal appropriate fare, and walked off to his cries of Policia!!

As far as "areas" to avoid.... Only thing I can think of, and it has cleaned up a lot in recent years, is Hlavni Nadrazi, the main train station. Not to "Avoid" it, but be aware that there are some impressivly talented pickpockets there. When I was a study abroad student there, I lost a camera out of a locked backpack walking through there...and no it didn't fall out, as the lock was busted off. Impressive...

It's gotten MUCH better in recent years though, which is odd.

Also, the Tram # 9 and Tram # 22 have their share of pickpockets. I had my wallet snatched on Tram # 9 near Vaclavske Namesti again, but managed to feel it happening (lord knows how) and slapped the wrist of the girl taking it. This caused her to drop it, a nice older gentlman to hand it to me, and the tram driver to come out of his booth, grab the woman who was a gypsy by the arm and forcefully thrust her off his tram.

But all in all, it's an amazingly safe city. But hey, I come from Chicago, isn't this the murder capital of the world or something....

-A